Inviscid approximation trajectories in high gradient magnetic separation

The precise conditions corresponding to the inviscid approximation in the axial configuration for high gradient magnetic separation (HGMS) trajectories has been modeled. Using red blood cells in a stopped-flow situation, it has been shown that the trajectories follow the analytical equations developed in the potential flow model. A small improvement is obtained by taking account of creeping flow corrections. The least well-defined parameter for nonspherical particles is the ratio (A/l) of area to characteristic length. By measuring (A/l) independently in terminal velocity experiments under gravity, a good fit is obtained to all the details of the trajectory equations without resort to adjustable parameters. The chief problems that arise are due to the nonsphericity of the red cell and the consequent possibility of (A/l) changing during the course of a trajectory.